Fabric softener

ABSTRACT

THE RINSE CYCLE FABRIC SOFTENER ADDITIVE AND A PROCESS FOR SOFTENING TEXTILE FABRICS THEREWITH, WHEREIN THE FABRIC SOFTENER ADDITIVE COMPRISES A COMPOUND OF THE FORMULA:   (R)N-P(+)-(R1-OH)(4-N) X-   WHEREIN R IS A C8-C20 ALKYL; R1 IS A LOWER ALKYL; N IS AN INTEGER OF 1, 2 OR 3, AND X IS A HALOGEN.

United States Patent 3,573,087 FABRIC SGFTENER James Douglas Barnhurst, Millington, N.J., assignor to Colgate-Palmolive Company, New York, N.Y. No Drawing. Filed Nov. 17, 1967, Ser. No. 683,815 Int. Cl. D06m 13/28 11.5. Cl. 117-47 7 Claims ABSTRACT OF THE DISCLOSURE The rinse cycle fabric softener additive and a process for softening textile fabrics therewith, wherein the fabric softener additive comprises a compound of the formula:

wherein R is a C -C alkyl; R is a lower alkyl; n is an integer of 1, 2 or 3, and X is a halogen.

The present invention relates to a rinse cycle fabric softener additive, and to a process for softening textiles therewith and, more particularly, to such a rinse cycle fabric softener additive and process wherein such additive comprises a cationic substituted phosphonium halide. The fabric softeners that are conventionally employed in consumer products are surface-active quaternary ammonium salts. While these conventional fabric softeners employed in the rinse cycle are generally very effective in the softening of textiles, such quaternary ammonium cationic surface active materials tend to have certain distinct disadvantages.

These conventional quaternary ammonium fabric softeners exhaust onto cellulosic fabrics, and because of this phenomenon repeated use of such fabric softeners often causes an uncontrolled build-up of softener on the fabric, to the point that some of the softened items begin to feel greasy and become, to some extent, water repellent. Accordingly, this is a grat disadvantage to the employment of quaternary ammonium fabric softeners, and thus greatly limits their use.

In addition, it has been observed that another consequence of the exhaustion of the quaternary ammonium surface active fabric softeners onto cellulosic fabrics is that such cationic salts attract the anionic color bodies that are frequently present in many Waters. In view of the attraction of these naturally occurring anionic color bodies, the softened fabrics tend to become discolored and yellowed. Again, this distinct disadvantage of the quaternary ammonium surface active fabric softeners greatly reduces the suitability of such materials.

Accordingly, it has long been the desire of the industry to produce a rinse cycle fabric softener which does not possess the inherent disadvantages of uncontrolled buildups and color body attraction associated with conventional quaternary ammonium materials. Thus, it has long been the desire of the industry to provide a rinse cycle fabric softener which can be fixed in a controlled quantity to a fabric in such a manner that one treatment provides an adequate level of softening over an extended period of time, This, therefore, would avoid the uncontrolled build-up of softener that occurs from the repeated usage of the quaternary ammonium salts, and therefore prevent the development of the greasy feel and water repellency associated with such materials.

3,573,087 Patented Mar. 30, 1971 In accordance with the present invention, it has now been discovered that certain substituted phosphonium halides, which can be either reacted with or exhausted onto a textile fabric, possess outstanding softening characteristics. In addition, it has been discovered in accordance with the present invention, that such substituted phosphonium halides can be affixed to the textile in a controlled quantity in such a manner that a single treatment provides an adequate level of softening over an extended period of time, thus eliminating the uncontrolled build-up of fabric softener associated with the use of conventional quaternary ammonium materials. In addition, it has been discovered in accordance with the present invention, that certain substituted phosphonium halides completely eliminate the inherent deficiencies and disadvantages of conventional surface active quaternary ammonium salts with respect to both the greasy feel and water repellency associated with uncontrolled build-up of the conventional fabric softeners, and to the yellowing of the fabric associated with the attraction of anionic color bodies by the quaternary ammonium salts.

Accordingly, it is a principal object of the present invention to provide a rinse cycle fabric softener additive and a process of softening textile fabrics therewith, which completely eliminate the inherent deficiencies associated with previously employed fabric softeners.

A further object of the present invention is to provide a cationic rinse cycle fabric softener additive comprising a substituted phosphonium halide, which rinse cycle fabric softener additive can be either reacted with or exhausted onto the textile fabric and eliminates the inherent deficiencies of uncontrolled build-up and attraction of colored bodies associated with previously employed materials.

A still further object of the present invention is to pro vide certain rinse cycle fabric softener additives comprising alkyl-hydroxy lower alkyl phosphonium halides and a process for softening textile fabrics therewith, wherein such fabric softener additive is capable of preserving the fabric whiteness even in colored water, and, withstands multiple detergent washings of the softened fabric.

Still further objects and advantages of the novel rinse cycle fabric softener additive of the present invention and process for softening textile fabrics therewith will become more apparent from the following, more detailed description of the present invention.

In accordance with the present invention, it has been discovered that certain substituted phosphonium halides are exceptionally effective rinse cycle fabric softener additives, and, such materials eliminate all of the inherent deficiencies and disadvantages of previously utilized quaternary ammonium surface active. materials. The rinse cycle fabric softener additives of the present invention correspond to the general formula wherein R is a C to C alkyl, R, is lower alkyl; 11 is an integer of 1, 2 or 3; and X is a halogen. While, as shown in the structural formula above, the phosphonium halide rinse cycle fabric softener additives of the present invention can contain 1, 2 or 3 C to C alkyl substituents, and preferred embodiment of the present invention is that in which the n is equal to '1. Such phosphonium halides will, therefore, be substituted with a single C to octyl tetradecyl isooctyl pentadecyl nonyl hexadecyl decyl heptadecyl undecyl stearyl dodecyl nonadecyl tridecyl eicosyl The hydroxy lower alkyl constituents present on the phosphonium halide of the present invention include:

hydroxy methyl l-hydroxy ethyl Z-hydroxy ethyl l-hydroxy propyl Z-hydroxy propyl S-hydroxy propyl l-hydroxy butyl 2-hydroxy butyl 3-hydroxy butyl 4-hydroxy butyl etc.

The following are representative compounds falling Within the above generic formula:

octyl-tris (hydroxymethyl) phosphonium bromide octyl-tris (hydroxymethyl) phosphonium chloride octyl-tris (hydroxymethyl) phosphonium iodide di(octyl)-bis (hydroxymethyl) phosphonium bromide di(octyl)-bis (hydroxymethyl) phosphonium chloride tri(octyl)hydroxymethyl phosphonium bromide tri(octyl)-hydroxymethyl phosphonium iodide octyl-tris (l-hydroxyethyl) phosphonium bromide octyl-tris (l-hydroxyethyl) phosphonium chloride octyl-tris (l-hydroxyethyl) phosphonium iodide di(octyl)-bis (l-hydroxyethyl) phosphonium bromide di (octyl -1-hydroxyethyl-l1ydroxymethyl phosphonium chloride tri(octyl) hydroxyethyl phosphonium bromide octyl-tris (l-hydroxypropyl) phosphonium bromide octyl-tris (Z-hydroxypropyl) phosphonium chloride di(octyl)-bis (l-hydroxypropyl) phosphonium bromide di (octyl) -2hydroxypropy1-hydroxymethyl phosphonium bromide octyl-tris (Z-hydroxybutyl) phosphonium bromide octyl-tris (Z-hyclroxybutyl) phosphonium chloride octyl tris (Z-hydroxybutyl) phosphonium iodide nonyl-tris (hydroxymethyl) phosphonium bromide nonyl-tris (hydroxymethyl) phosphonium chloride nonyl-tris (hydroxymethyl) phosphonium iodide di(nonyl)-bis (hydroxymethyl) phosphonium bromide tri(nonyD-hydroxymethyl phosphonium bromide nonyl tris (l-hydroxyethyl) phosphonium bromide di(nony1)-bis (l-hydroxyethyl) phosphonium bromide tri(nonyl) hydroxyethyl phosphonium bromide nonyl tris (Z-hydroxypropyl) phosphonium chloride di nonyl) -2-hydroxypropyl-hydroxymethyl phosphonium bromide nonyl tris (2-hydroxybutyl) phosphonium chloride decyl-tris (hydroxymethyl) phosphonium bromide decyl-tris (hydroxymethyl) phosphonium chloride decyl-tris (hydroxymethyl) phosphonium iodide di(decyD-bis (hydroxymethyl) phosphonium bromide tri(decyD-hydroxymethyl phosphonium bromide decyl tris (1-hydroxyethyl) phosphonium bromide di(decyl)-bis (l-hydroxyethyl) phosphonium bromide tri(decyl) hydroxyethyl phosphonium bromide decyl tris (Z-hydroxypropyl) phosphonium chloride di (decyl) 2-hyd1oxypropyl-hydroxymethyl phosphonium bromide decyl-tris (Z-hydroxybutyl) phosphonium chloride dodecyl-tris (hydroxymethyl) phosphonium bromide dodecyl-tris (hydroxymethyl) phosphonium chloride dodecyl-tris (hydroxymethyl) phosphonium iodide di(dodecyl)-bis (hydroxymethyl) phosphonium bromide 5 di(dodecyl)-bis (hydroxymethyl) phosphonium chloride tri(dodecyl)-hydroxymethyl phosphonium bromide tri(dodecyl)-hydroxymethyl phosphonium iodide dodecyl tris (l-hydroxyethyl) phosphonium bromide dodecyl tris (l-hydroxyethyl) phosphonium chloride dodecyl tris (l-hydroxyethyl) phosphonium iodide di(dodecyl)-bis (l-hydroxyethyl) phosphonium bromide di(dodecyl)-1-hydroxyethyl-hydroxymethyl phosphonium chloride tri(dodecyl) hydroxyethyl phosphonium bromide dodecyl tris (l-hydroxypropyl) phosphonium bromide dodecyl tris (Z-hydroxypropyl) phosphonium chloride di(dodecyl)-bis (l-hydroxypropyl phosphonium bromide di(dodecyl)-2-hydroxypropyl-hydroxymethyl phosphonium bromide dodecyl tris (2-hydroxybutyl) phosphonium bromide dodecyl tris (Z-hydroxybutyl) phosphonium chloride dodecyl tris (Z-hydroxybutyl) phosphonium iodide tridecyl-tris (hydroxyrnethyl) phosphonium bromide tridecyl-tris (hydroxymethyl) phosphonium chloride tridecyl-tris (hydroxymethyl) phosphonium iodide di(tridecyl)bis (hydroxymethyl) phosphonium bromide tri(tridecyl)-hydroxymethyl phosphonium bromide tridecyl-tris (l-hydroxyethyl) phosphonium bromide di(tridecyl)-bis (l-hydroxyethyl) phosphonium bromide 30 tri(tridecyl) hydroxyethyl phosphonium bromide tridecyltris (2-hydroxypropyl) phosphonium chloride di (tridecyl -2-hydroxypropyl-hydroxymethyl phos phonium bromide tridecyl tris (2-hydroxybutyl)phosphonium chloride 35 hexadecyl-tris (hydroxymethyl) phosphonium bromide heXadecyl-tris (hydroxymethyl) phosphonium chloride hexadecyl-tris (hydroxymethyl) phosphonium iodide di(hexadecyD-bis (hydroxymethyl) phosphonium bromide tr1(hexadecyl)-hydroxymethyl phosphonium bromide hexadecyl tris (l-hydroxyethyl) phosphonium bromide di(hexadecyD-bis (l-hydroxyethyl) phosphonium bromide tri(hexadecyl)-hydroxyethyl phosphonium bromide hexadecyl tris (Z-hydroxypropyl) phosphonium bromide di(hexadecyl)-hydroxypropyl-hydroxyrnethyl phosphonium bromide hexadecyl tris (Z-hydroxybutyl) phosphonium chloride stearyl-tris (hydroxymethyl) phosphonium bromide stearyl-tris (hydroxymethyl) phosphonium chloride stearyl-tris (hydroxymethyl) phosphonium iodide di(stearyl)-bis (hydroxymethyl) phosphonium bromide di-(stearyl)-bis (hydroxymethyl) phosphonium chloride tri (stearyD-hydroxymethyl phosphonium bromide tri(stearyD-hydroxymethyl phosphonium iodide stearyl-tris (l-hydroxyethyl) phosphonium bromide stearyl-tris (l-hydroxyethyl) phosphonium chloride stearyl-tris (l-hydroxyethyl) phosphonium iodide di(stearyl)-bis (l-hydroxyethyl) phosphonium bromide di(stearyl)-1-hydroxyethyl-hydroxymethyl phosphonium chloride tri(stearyl) hydroxyethyl phosphonium bromide stearyl-tris (l-hydroxypropyl) phosphonium bromide stearyl tris (2-hydroxypropyl) phosphonium chloride di(stearyl) bis (l-hydroxypropyl) phosphonium bromide di(stearyl)-2-hydroxypropyl-hydroxymethyl phosphonium bromide stearyl tris (Z-hydroxybutyl) phosphonium bromide stearyl tris (Z-hydroxybutyl) phosphonium chloride stearyl tris (Z-hydroxybutyl) phosphonium iodide eicosyl-tris (hydroxymethyl) phosphonium bromide eicosyl-tris (hydroxymethyl) phosphonium chloride eicosyl-tris (hydroxyrnethyl) phosphonium iodide di(eicosyl)-bis (hydroxymethyl) phosphonium bromide tri(eicosyl)-hydroxymethyl phosphonium bromide eicosyl tris (l-hydroxyethyl) phosphonium bromide eicosyl tris (l-hydroxyethyl) phosphonium iodide tri(eicosyl) hydroxyethyl phosphonium bromide eicosyl tris (Z-hydroxypropyl) phosphonium chloride di (eicosyl) -2-hydroxypropyl-hydroxymethyl phosphonium bromide eicosyl tris (2-hydroxybutyl) phosphonium chloride The rinse cycle fabric softener additive of the present invention is generally present as a concentrated aqueous dispersion of such softening agent, which concentrated aqueous dispersion is readily dispersible in the rinse cycle water of the washing operation. Whilethe fabric softener can be employed in varied amounts, depending on the degree of softness desired, since the rinse cycle fabric softener additives of the present invention do not tend to produce an uncontrolled buildup or attract colored bodies, it is preferred to employ an amount of fabric softener so that the concentration during the rinse cycle varies from about 0.05% by weight to about by weight of the aqueous system. Of course, lesser or greater concentrations can be suitably employed where desired for particular purposes.

While the rinse cycle fabric softener additive of the present invention is preferably added to the rinse cycle system as a concentrated aqueous dispersion, it is, of course possible to produce a fluid emulsion of the rinse cycle fabric softener additive by including within the concentrated system a conventional non-ionic emulsifier. Additionally, the concentrated aqueous system containing the rinse cycle fabric softener additive of the present invention can be very readily formulated with other conventional auxiliary additives, such as optical brighteners, inert fillers, dyes, perfumes, etc.

In practicing the process of the present invention, the rinse cycle fabric softener additive or the concentrated dispersion or emulsion thereof is merely added to the rinse cycle in the washing operation. In this way, the fabric softener will be dispersed uniformly throughout the rinse cycle water in an amount sufficient to create the desired softness or feel of the textile fabrics. The particular rinse cycle fabric softeners of the present invention are effective in a softening action by a simple warming of the suspension of the phosphonium halide in the presence of the fabric to be so softened. Accordingly, no elaborate or special procedure need be used in employing the rinse cycle fabric softener additive of the present invention, it being merely necessary to contact the fabric with the additive during the rinse cycle of the washing operation.

Thus, in accordance with the present invention, it has been found possible to preserve the fabric whiteness even in colored water by employing the particular rinse cycle fabric softener additives of the present invention. In addition, it has been found that there is no uncontrolled buildup of softener on the fabric, as is the case with the employment of conventional surface additive quaternary ammonium salts. Furthermore, it has been discovered in accordance with the present invention, that it is possible to affix a controlled quantity of fabric softener to the fabric by employing the process of the present invention, such that one treatment with the fabric softener additive of the present invention provides an adequate level of softening over an extended period of time, which level of softening is not adversely affected by one or more washings with detergents. Thus, wherein ordinary quaternary ammonium fabric softeners tend to produce disadvantageous results both as to feel and color, and lose their softening characteristics with the next succeeding washing of the fabric, the phosphonium halides of the present invention do not, in any way, possess such disadvantages.

The fabric softener compound and process of softening fabrics therewith of the present invention will now be further illustrated by reference to the following specific examples. It is to be understood, of course, that these examples are presented for purposes of illustration only, and the present invention is in no way to be deemed as limited thereby.

6 EXAMPLE 1 Swatches of terry cloth were cut to 8" x 8" dimensions, each swatch weighing approximately 12 g. They were marked A, B and E with a laundry marker. Each swatch was then washed in a Tergotometer in one liter of deionized water at F., each swatch then being squeezed as dry as possible by hand.

Dodecyl-tris(hydroxymethyl)phosphonium bromide 2.4 g. was suspended in 240 ml. of water and the suspension was neutralized (pH 7.0-7.2) with dilute triethanolamine. Swatch A was then immersed in the suspension, and the entire contents of the vessel was stirred for fifteen minutes. One gram of ammonium chloride in 10 ml. of water was then added with stirring, and the pH of the suspension was adjusted to pH 7.5 with a saturated solution of sodium pyrophosphate. The contents of the vessel were then stirred and heated to 190 F. during the course of about twenty minutes. During this time, sodium pyrophosphate solution was added from time to time to keep the pH between 7.2 and 7.5. During the beginning of the warming period, the mixture was cloudy, but at about 110 F. the cloudiness began to disappear, and by F. the liquid was transparent. The contents were then kept at F. at pH 7.2-7.5 until the pH no longer tended to diminish. This took approximately fifteen minutes, during which time the pyrophosphate solution was occasionally added. Concentrated ammonium hydroxide, 1.5 ml. was then added and after mixing thoroughly, the swatch was removed and squeezed to remove as much liquid as possible. The swatch was then dried at 105 -1 15 C. in an oven.

Swatch B was treated in the same manner as A, except that only 0.24 g. of the phosphonium salt was used. Again, the suspension of phosphonium salt was initially cloudy but again, on warming, the cloudiness cleared up, this time at a lower temperature.

Swatch E was treated in a manner similar to swatches A and B, except that no phosphonium salt was used.

After drying, the swatches were compared for softness by passing the swatches through the fingers. In ten blind comparisons the results were A B E in each case, thereby indicating that the use of the phosphonium salt caused the development of softness on swatches A and iBS7 The swatches were then heated in an oven for fifteen minutes at 140l45 C. The swatches were then washed, each in a liter of deionized water containing 0.1 g. of Igepal CO630 (a commercial nonionic detergent) for twenty minutes at 120 F., and rinsed five minutes at 120 F. in deionized water. The swatches were then air dried.

After drying, the swatches were again evaluated for softness. Again, in ten blind comparisons swatch A was found softer than B, and B softer than E.

After three more Igepal washes, the switches were again evaluated for softness. Again, in ten blind comparisons swatch A" was found softer than B, and B softer than E.

At this point, swatch A had a luxurious billowy fluify softness that swatch B had to a slightly lesser extent.

The swatches that were treated in accordance with the present invention, and blank swatches were then washed in one meter of FAB (0.15%) in deionized water at 120 F. for 10 minutes. They were rinsed also at 120 F. for five minutes, and air dried.

The swatches were then again compared for softness by hand in ten blind comparisons. In each case, the swatches that had received the treatment with the rinse cycle fabric softener additive of the present invention were superior in softness to those which received no such treatment.

Again, the swatches were washed in FAB and rinsed and dried, and compared again for softness in ten blind comparisons. Here again, the swatches that had received the treatment with the fabric softener of the present invention were superior to the swatches that received no such treatment, and could be distinguished by softness in all cases. This, therefore, indicates that the employment of the fabric softener additive of the present invention survived at least two anionic washes, when the fabric softener is exhausted on to the fabric by the procedure of this example.

EFQAMPLE 2 A suspension of dodecyl-tris(hydroxymethyl)phosphonium bromide was prepared by suspending 560 mg. of the phosphonium salt in one liter of water. Four hundred twenty-five ml. portions of the suspension were then put in the buckets of a Tergotometer and warmed to 120 F.

An 8" x 8 terry cloth swatch weighing about 12 g. was then put into the bucket and the bucket was agitated at 120 F. for twenty minutes. The swatch was then removed from the Tergotometer, squeezed as much as possible by hand, and air dried substantially, horizontally.

After drying, the swatch was evaluated by hand for softness. In each of ten blind comparisons, the swatch treated with the phosphonium salt was judged softer than a blank swatch.

The treated swatch was then washed in the Tergotometer in one liter of water containing 0.1 g. of Igepal CO-630 at 120 F. for fifteen minutes. It was then rinsed in the Tergotometer in one liter of water at 120 F. for five minutes. After line drying, the washing, rinsing and drying was repeated.

The swatch treated with the phosphonium salt was then compared for softness with the blank. In each of ten blind comparisons, the treated swatch was found to be softer than the blank.

Here again, the swatch treated as above as well as two blank swatches, were washed in one liter of FAB (0.15%) in deionized water at 120 F. for ten minutes. Again, the swatches were rinsed, also, at 120 F. for five minutes and air dried.

The swatch treated as above was compared with the blank swatches for softness by hand evaluations in ten blind comparisons. In each case, the swatch treated by the above procedure was found superior in softness to those which had received no such treatment. Accordingly, this test illustrates that even the simple warming of the suspension of the phosphonium halite fabric softener of the present invention in contact with the fabric to be treated, is sutficient to create softness in the fabric, which softness survives an anionic washing.

EXAMPLE 3 Four 4" x 4" terry cloth swatches were stitched along the edges to minimize fraying. The Rd and b reflectance value of the front and back sides of the swatches (marked 1, 2, 3 and 4) were measured. The averages of eight measurements (four of the front and four of the back) of each reflectance value for each swatch were as follows:

Reflectance values Swatch 1 Swatch 2 Swatch 3 Swatch 4 Rd 88.3 88. 87.3 86. 9 b +3. 4 +3. 4 +3. 4 +3. 4

The swatches were then treated individually for twenty minutes at 120 F. in a Tergotometer in one liter of J. C. tap water with the following variations:

8 (4) To the water in which swatch #4 was treated,

nothing was added.

The swatches were then removed from the Tergotometer, squeezed out by hand and air dried.

Visually, swatch #2, the swatch softened with dodecyltris(hydroxymethyl)phosphonium bromide, was about as white as swatch #4, the blank swatch. The other two swatches, one softened with a tetraalkyl-phosph-onium salt and the other softened with a tetraalkylammonium salt, were much more highly colored.

The reflectance values of the treated swatches were as follows:

Reflectance values Swatch 2 Swatch 3 Swatch 1 Swatch 4 The changes in reflectance values as a result of the treatment are as follows:

Changes in reflectance Swatch 2 Swatch 3 Swatch 1 Swatch 4 A negative change in Rd reflectance means an increase in grayness.

A positive change in b reflectance means an increase in yellowness, while a negative change in b reflectance means an increase in blueness. It can be seen that the two tetraalkyl salts cause substantial increases in both grayness and yellowness while dodecyl-tris(hydroxymethyl)phosphoniurn bromide caused substantially less grayness and no yellowness.

EXAMPLE 4 The following rinse cycle fabric softener additives were added in aqueous dispersions to the rinse cycle in a conventional washing machine, the laundry being washed including wool, cotton and synthetic textile materials, e.g. polyester and nylon articles. In all cases, the addition of the concentrated fabric softener additive was made so as to prepare a rinse cycle system containing 0.1, 1, and 5% of the phosphonium halide additive;

In all cases, when an evaluation was made between the various laundry articles wherein the product softener additive of the present invention was employed in the rinse cycle, and those laundry articles where no fabric softener was employed, those articles treated in accordance with the present invention in all cases, were superior in softness.

While the present invention has been described primarily with respect to the foregoing specific examples, it is to be understood that the present invention is in no way to be deemed as limited thereby, but must be construed as broadly as all or any equal thereof.

I claim:

1. In a process for laundering clothes in a washing machine including a washing cycle with detergent and a rinse cycle with water, the improvement which comprises treating said clothes in said rinse cycle with an elfective fabric softening amount of a compound of the formula:

P (R1011) (4-1:) X-

R is an alkyl of from about C to C R is lower alkyl;

12 is an integer of 1, 2 or 3; and

X is a halogen.

2. The process of claim 1 wherein the temperature of the water in the rinse cycle is about 120 F.

3. The process of claim 1 wherein the amount of said compound varies from about 0.5 to 10% by weight based on the total weight of the aqueous system in the rinse cycle.

4. The process of claim 1 wherein n is 1.

wherein References Cited UNITED STATES PATENTS 2,693,427 11/1954 Kingsford 117-139.5X 2,837,446 6/1958 Cohen et a1 117139.5X 2,950,253 8/1960 Kling et al. 2528.8X 3,122,502 2/1964 Waldman 2528.8 3,349,033 10/1967 Zuccarelli 2528.8X

FOREIGN PATENTS 1,293,706 9/1962 France 260-606.5

881,656 11/1961 Great Britain 260606.5

HERBERT B. GUYNN, Primary Examiner 

